Abstract:
The electron transport layer (ETL) is a key component specially in planar structure solar
cells. It is used to collect the electrons and reduce the recombination losses. ETL is
chosen by considering the conductance, electrical trap density, and energy bandgap.
Thus, TiO2 and CdS are widely used as ETL in solar cells. Some simulation studies
show the possibility of efficient solar cells minimizing or eliminating traditional
electron transport material. However, the reported efficiencies are less compared to the
efficiency of solar cells that use ETL. In this study, we developed the Sb2S3 solar cells
due to the potential of Sb2S3 semiconductor material. The CdS solution was prepared
by adding thiourea (TU) and cadmium acetamide (Cd(ac)) in 2-methoxyethanol and
stirring until they completely dissolved. Likewise, a TiO2 precursor solution was
prepared by mixing titanium isopropoxide and di-ethanolamine in butan-1-ol. The CdS
was spin-coated on the TiO2 layer to prepare the dual-layer ETL while TiO2 was used
as a single ETL. Also, the thickness of CdS was controlled by the spinning speed of
2500, 3000, and 3500 rpm. The use of a dual ETL enhanced the charge collection hence,
the performance of solar cells was improved compared to the single ETL. The
increasing efficiency was observed up to a certain spinning speed of CdS then it was
reduced. At 3000 rpm speed of CdS, the highest efficiency of 2.23% was achieved for
dual layer ETL. This efficiency was nearly two times greater than a single ETL in our
configuration.
